Physics

1) Reproduce simple gravity from scratch

The white ball is powered by this script.

The red ball uses Unity Physics (FixedUpdate)

using System.Collections;using System.Collections.Generic;using UnityEngine;
public class PhysicsBall : MonoBehaviour { public GameObject ball; public GameObject ballRb; public GameObject floor; Vector3 posOriginal; [Range(.05f, .5f)] float gravityMagnitude = 9.8f; bool ynCollision = false; Vector3 velocity = Vector3.zero;
void Start () { posOriginal = ball.transform.position; Debug.Log("gravity:" + Physics.gravity.magnitude + "\n"); Debug.Log("deltaTime:" + Time.deltaTime + "\n"); InvokeRepeating("ResetBall", 6, 6); } void Update () { UpdateCollision(); if (ynCollision == true) return; UpdateGravity(); }
void UpdateGravity() { velocity.y -= gravityMagnitude * Time.deltaTime; ball.transform.position += velocity * Time.deltaTime; }
void UpdateCollision() { float distY = Mathf.Abs(ball.transform.position.y - floor.transform.position.y - ball.transform.localScale.y/2 - floor.transform.localScale.y/2); if (distY < .1f) { ynCollision = true; } }
void ResetBall() { ball.transform.position = posOriginal; velocity = Vector3.zero; ballRb.transform.position = posOriginal + new Vector3(0, 0, 3); ynCollision = false; }}

Adjusting gravity for sphere

using System.Collections;using System.Collections.Generic;using UnityEngine;
public class PhysicsOrbitBounce : MonoBehaviour { public GameObject[] sats; public GameObject globe; Vector3[] velocitys; float grav = 9.8f;
// Use this for initialization void Start () { velocitys = new Vector3[sats.Length]; for (int n = 0; n < sats.Length; n++) { velocitys[n] = sats[n].transform.forward * Random.Range(.5f, 3f); } } // Update is called once per frame void Update () { for (int n = 0; n < sats.Length; n++) { Physics.gravity = Vector3.Normalize(globe.transform.position - sats[n].transform.position) * grav; velocitys[n] += Physics.gravity * grav * Time.deltaTime; sats[n].transform.position += velocitys[n] * Time.deltaTime; } }}

First Try

lines go through each other
velocity and torque need work
need to think about objects

Inside Poly

summing delta angles
0 (within tolerance) is outside
360 is inside

Reflect

inside / out works well
reflect with static
reflect with dynamic

To Do

torque / rotation

Brushes

vectors from center to points are like brushes
brush hair ends are sensors
when any two hairs from different brushes touch, each brush moves
avoid vector is end point minus center

Polygons.cs

using System.Collections;using System.Collections.Generic;using UnityEngine;
public class Polygons : MonoBehaviour { List<Poly> polys; float tol = .05f; int cntFrames;
// Use this for initialization void Start () { polys = new List<Poly>(); List<Vector3> points; points = new List<Vector3>(); float rad0 = 3; Vector3 cen0 = Vector3.zero; float rad = 1; Poly poly; for (int t = 0; t < 20; t++) { points.Clear(); Vector3 cen = Random.insideUnitCircle; rad = Random.Range(rad0/10, rad0/5); for (float ang = 0; ang < 360; ang += 15) { float x = cen.x + rad * Mathf.Cos(ang + Mathf.Deg2Rad); float z = cen.z + rad * Mathf.Sin(ang + Mathf.Deg2Rad); points.Add(new Vector3(x, 0, z)); } poly = new Poly(points); poly.velocity = new Vector3(Random.Range(0, 1f), 0, Random.Range(0, 1f)); poly.torque = new Vector3(0, Random.Range(-30f, 30f), 0); polys.Add(poly); } // points.Clear(); for (float ang = 0; ang < 360; ang += 2.5f) { float x = cen0.x + rad0 * Mathf.Cos(ang + Mathf.Deg2Rad); float z = cen0.z + rad0 * Mathf.Sin(ang + Mathf.Deg2Rad); points.Add(new Vector3(x, 0, z)); } poly = new Poly(points); poly.velocity = Vector3.zero; poly.torque = Vector3.zero; polys.Add(poly); } // Update is called once per frame void Update () { foreach(Poly poly in polys) { poly.Move(); poly.Rotate(); } FindIntersection(); cntFrames++; }
void ShowFps() { }
void FindIntersection() { for (int n1 = 0; n1 < polys.Count; n1++) { for (int n2 = 0; n2 < polys.Count; n2++) { if (n1 != n2) { foreach(GameObject go1 in polys[n1].goPoints) { Vector3 p1 = go1.transform.position; foreach (GameObject go2 in polys[n2].goPoints) { Vector3 p2 = go2.transform.position; if (ArePointsNear(p1, p2) == true) { polys[n1].Avoid(p1); polys[n2].Avoid(p2); break; } } } } } } }
bool ArePointsNear(Vector3 p1, Vector3 p2) { bool yn = false; float dist = Vector3.Distance(p1, p2); if (dist < tol) { yn = true; } return yn; }}
public class Poly : MonoBehaviour { public List<Vector3> points; public GameObject parent; public Vector3 velocity; public List<GameObject> goPoints; public Vector3 torque; public Poly(List<Vector3> points0) { parent = new GameObject("poly"); //parent.transform.position = Vector3.zero; points = new List<Vector3>(); goPoints = new List<GameObject>(); Vector3 sum = Vector3.zero; foreach (Vector3 p in points0) { sum += p; } parent.transform.position = sum / points0.Count; for (int n = 0; n < points0.Count; n++) { Vector3 p = points0[n]; points.Add(p); GameObject go = GameObject.CreatePrimitive(PrimitiveType.Sphere); go.transform.localScale = new Vector3(.05f, .05f, .05f); go.transform.position = p; go.transform.parent = parent.transform; goPoints.Add(go); } } public void Avoid(Vector3 point) { float magnitude = velocity.magnitude; Vector3 vector = parent.transform.position - point; velocity = Vector3.Normalize(vector) * magnitude; } public void Move() { parent.transform.position += velocity * Time.deltaTime; } public void Rotate() { parent.transform.eulerAngles += torque * Time.deltaTime; }}

Sponge

smoothing used with avoid
goal is for sensors to retract for deformation